Compressor

ABSTRACT

The present invention provides a compressor having casings fixed together in a manner allowing the compressor to have a reduced sized as well as reusability. 
     The compressor according to the present invention comprises a plurality of casings ( 1   a,    1   b ) each having an open end designed to be brought into butt contact, the casings being arranged with the open ends in butt contact with each other, thereby constituting a pressure vessel enclosing a compressing unit; a flange-like projection ( 3 ) formed on the outer circumference of the open end of each of the casings, the projections of the casings butted together forming a pair; and a plurality of fixing members ( 4   a  to  4   c ) each in a shape corresponding to a section which would be obtained by dividing the open end of the casing, and having a groove inside, the groove being designed to engage with the paired projections butted together. The open ends of the casings butted together are fixed by the fixing members arranged to surround the casings, each in engagement with the paired projections, and welded to each other.

TECHNICAL FIELD

This invention relates to a compressor having a compressing unit enclosed in a pressure vessel.

BACKGROUND ART

In automotive air conditioning systems, domestic air conditioners and refrigerators, etc., a refrigeration cycle is operated with a sealed compressor.

In many of such compressors, a pressure vessel enclosing a compressing unit is constructed by bringing open ends of a pair of cylindrical casings into butt contact, as disclosed in Japanese Patent Application KOKAI Publication 2005-54667.

Since the compressing unit placed inside the pressure vessel is a machine, the possibility of its requiring regulation or repair needs to be taken into consideration.

Thus, there is used a structure considering the possible need to separate the compressor casings, in which each casing has outwardly-projecting bolt-insertion boss portions provided around the open end, at several locations, to allow the casings to be fixed together by fastening their boss portions by bolts, as disclosed in Japanese Patent Application KOKAI Publication 2005-54667.

In order to produce the holding force overcoming the internal pressure by tightening bolts, use of large-diameter bolts is required. This however not only requires large-diameter bolts; the boss portions into which the bolts are inserted also require a fairly large projection size. Thus, the resulting compressor tends to be large in size.

Thus, for the compressors in domestic air-conditioners and refrigerators, etc., a technique of welding together the open ends of the casings is used to offer high holding strength, as disclosed in Japanese Patent Application KOKAI Publication Hei 11-324920.

The structure with the casings welded together is superior in holding strength but inferior in product reusability. Specifically, if, for example a compressing unit enclosed in the paired casings requires regulation or repair, repair of internal machinery cannot be conducted without breaking the casings. Breaking the casings affects not only the casings but also the compressing unit inside the casings. Thus, it is virtually difficult to continue to use the same compressor.

There is therefore a demand for a technique of fixing the casings together which allows the compressor to have a reduced size as well as reusability.

DISCLOSURE OF THE INVENTION

The primary object of the present invention is to provide a compressor having casings fixed together in a manner allowing the compressor to have a reduced size as well as reusability.

The compressor according to the present invention comprises a plurality of casings each having an open end designed to be brought into butt contact, the casings being arranged with the open ends in butt contact with each other, thereby constituting a pressure vessel enclosing a compressing unit; a flange-like projection formed on the outer circumference of the open end of each of the casings, the projections of the casings butted together forming a pair; a plurality of fixing members each in a shape corresponding to a section which would be obtained by dividing the open end of the casing, and having a groove inside, the groove being designed to engage with the paired projections butted together, wherein the open ends of the casings butted together are fixed by the fixing members arranged to surround the casings, each in engagement with the paired projections, and welded to each other.

In the compressor according to the present invention, the open ends of the casings are fixed together by bringing their flange-like projections into engagement with the fixing members which together constitute an annular shape. In this structure, the projection of each casing may be of a small size allowing the engagement. Thus, the casings are fixed together with high fixing strength, without a large projection as required when bolts are used. Further, if the compressing unit placed inside the casings requires regulation or repair, the fixing members can be removed from the casings only by cutting them, and the casings can be separated hereupon. This allows reuse of components of the compressor.

Thus, the casings are fixed together in a manner allowing the compressor to have a reduced size as well as reusability.

In the compressor according to the present invention, it is preferable that each of the paired projections have a rear face opposite to the open end, said rear face being an inclined surface allowing the paired projections to have a root portion greater than an opening width of the groove.

In this compressor structure, first, the fixing members are arranged annularly around the casings, each in engagement with the paired projections butted together. The fixing members are then pushed toward the center of the casings. At this time, the paired projections with the inclined surfaces act on the edges of the side walls of the groove like a wedge, so that the casing ends push on each other. Then, in this state, the fixing members are welded to each other, so that the casings are fixed together firmly. Even after the casings are fixed together, an increase in the pressure inside the casings results in an increase in the force applied by each inclined surface on the corresponding side wall of the groove, because the paired projections with the inclined surfaces act like a wedge. Consequently, the casing ends push on each other with an increased force. Thus, the pressure vessel composed of the casings is free from leakage and has an increased reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the external appearance of a compressor according to an embodiment of the present invention,

FIG. 2 is a cross-sectional view along line A-A in FIG. 1,

FIG. 3 is a perspective view showing casings with a flange-like projection, and

FIG. 4 is a perspective view showing how the casings are fixed together using flange-like projections and fixing members which are set in an annular arrangement.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be explained on the basis of an embodiment shown in FIGS. 1 to 4.

FIG. 1 shows the external appearance of a compressor, which is, for example a motor-driven (sealed) compressor for an automotive air-conditioning system. FIG. 2 shows a cross-section along line A-A in FIG. 1, and FIGS. 3 and 4 show how to fix casings.

In FIG. 1, reference character 1 denotes a cylindrical housing of the motor-driven compressor (pressure vessel in the present application). As shown in FIG. 3, the housing 1 is divided into cylindrical outer coverings, for example a cylindrical casing 1 a closed at an end and a cylindrical casing 1 b likewise closed at an end. The open ends of the casing 1 a, 1 b are designed to be brought into butt contact. The housing 1 is constructed by bringing the open ends into butt contact and fixing them together in a manner described later.

A compressing unit 10 consisting of a scroll compressing mechanism, for example, is placed in the casing 1 a constituting a half of the housing 1. In the other casing 1 b, an electric driving unit 12 consisting of an electric motor, for example, is placed together with an inverter unit 13 controlling the electric driving unit 12. The compressing unit 10 performs compressing operation by rotation being transferred from an output (not shown) of the electric driving unit 12 to an input (not shown) of the compressing unit 10. By the compressing operation, a refrigerant is sucked from outside the housing, compressed, and discharged through a discharge port 10 a of the housing 1 a after flowing through the housing 1.

The open ends of the casings 1 a, 1 b butted together are fixed by a structure offering high holding strength. Specifically, the casings 1 a, 1 b butted together are fastened together by engagement as shown in FIGS. 3 and 4.

More specifically, the casings 1 a, 1 b each have a flange-like projection 3 formed on the outer circumference of the open end as shown in FIG. 3, and fixing members 4 a to 4 c for fixing the projections 3, 3, as shown in FIG. 4, are brought into engagement with the projections. As shown in FIG. 2, the projections 3 each have a flat, butting face 3 a extending in the plane of the open end, and a rear inclined face opposite to the open end. More specifically, the rear face, denoted by reference character 3 b, is inclined such that the projection 3 has thickness increasing toward its root.

The fixing members 4 a to 4 c are, for example members which would be obtained by dividing a member of a shape corresponding to the open ends of the casings 1 a, 1 b, as shown in FIG. 4. Specifically, the fixing members 4 a to 4 c are arc-shaped members which would be obtained by divining an annular frame member formed to the roundness of the casings 1 a, 1 b, into three, for example. The fixing members 4 a to 4 c are channel members with a groove inside, as shown in FIG. 4. The groove 5 extends in the inner surface of each fixing member over the entire length thereof. The groove 5 has an opening width capable of receiving the paired projections 3 butted together, except for their root portion. This is because the inclined surface 3 b of the paired projections are inclined such that the paired projections have a root portion greater than the opening width of the groove 5.

The casings 1 a, 1 b are fixed together as follows: First, as shown in FIGS. 2 and 4, the fixing members 4 a to 4 c are arranged annularly around the casings 1 a, 1 c, each in engagement with the paired projections 3, 3 butted together. Then, the fixing members 4 a to 4 c surrounding the casings 1 a, 1 b are pushed toward the center of the casings 1 a, 1 b as indicated by arrows A in FIG. 4, to bring the edges of the side walls 5 a of the groove 5 into contact with the inclined faces 3 b. Since the paired projections act like a wedge at this time, the casing ends push on each other. Then, the fixing members 4 a to 4 c arranged annularly are welded to each other at their ends using a welding machine not shown, and thus fixed as shown in FIGS. 1 and 2. Reference character X in FIG. 1 denotes a weld.

Thus, the ends of the casings 1 a, 1 b are fixed together by bringing the paired annular projections 3, 3, into engagement with the annular groove 5 of the fixing members fitted outside.

In this manner of fixing, pressure acting on the inner side of the casings 1 a, 1 b, as seen in the motor-driven compressor, effectively increases the fixing strength. Further, the casings 1 a, 1 b only requires a small projection allowing the engagement.

In other words, this structure allows the casings 1 a, 1 b to be fastened together with high fixing strength, without large projections as required when bolts are used.

Suppose that the compressing unit 10 placed inside the casings 1 a, 1 b requires regulation or repair.

In this case, the fixing members 4 a to 4 c welded together are cut and removed from the casings 1 a, 1 b. The casings 1 a, 1 b thus released from engagement can be separated to allow the regulation or repair of the compressing unit 10 placed inside. This allows reuse of components of the motor-driven compressor, except for the fixing members 4 a to 4 c. In other words, an increased number of components of the motor-driven compressor can be used continuously.

Thus, the casings 1 a, 1 b can be fixed together in a manner allowing the motor-driven compressor to have a reduced size as well as enhanced reusability. Particularly, when the projection 3 has an inclined rear face 3 b, an increase in the pressure inside the casings 1 a, 1 b, indicated by reference character P in FIG. 2, results in an increase in the force applied by each inclined surface 3 b on the edge of the corresponding side wall 5 a of the groove 5, because the paired projections with the inclined surfaces act like a wedge. Consequently, the casings 1 a, 1 b push on each other with an increased force. Thus, the pressure vessel composed of the casings 1 a, 1 b is free from leakage between the casings and has an increased reliability.

The present invention is not restricted to the above-described embodiment but may be modified in various ways without departing from the scope and spirit of the present invention. For example, although in the above embodiment, the present invention is applied to a motor-driven compressor, application of the present invention is not restricted to this The present invention may be applied to other types of compressors for use in automotive air-conditioning systems, sealed compressors for use in domestic air conditioners and refrigerators, etc. 

1. A compressor, comprising: a plurality of casings each having an open end designed to be brought into butt contact, the casings being arranged with the open ends in butt contact with each other, thereby constituting a pressure vessel enclosing a compressing unit, a flange-like projection formed on the outer circumference of the open end of each of the casings, the projections of the casings butted together forming a pair, a plurality of fixing members each in a shape corresponding to a section which would be obtained by dividing the open end of the casing, and having a groove inside, the groove being designed to engage with the paired projections butted together, wherein the open ends of the casings butted together are fixed by the fixing members arranged to surround the casings, each in engagement with the paired projections, and welded to each other.
 2. The compressor according to claim 1, wherein each of the paired projections has a rear face opposite to the open end, said rear face consisting of an inclined surface allowing the paired projections to have a root portion greater than an opening width of the groove. 